Methodologic Differences Across Studies of Patients With Atrial Fibrillation Lead to Varying Estimates of Stroke Risk

Stroke and bleeding risk in atrial fibrillation with CHA2DS2-VASC risk score of one: the Norwegian AFNOR study

BACKGROUND AND AIMS

The benefit of oral anticoagulant (OAC) therapy in atrial fibrillation (AF) and intermediate stroke risk is debated. In a nationwide Norwegian cohort with a non-sex CHA2DS2-VASc risk score of one, this study aimed to investigate (i) stroke and bleeding risk in AF patients with and without OAC treatment, and (ii) the risk of stroke in non-anticoagulated individuals with and without AF.

METHODS

A total of 1 118 762 individuals including 34 460 AF patients were followed during 2011-18 until ischaemic stroke, intracranial haemorrhage, increased CHA2DS2-VASc score, or study end. One-year incidence rates (IRs) were calculated as events per 100 person-years (%/py). Cox regression models provided adjusted hazard ratios (aHRs [95% confidence intervals]).

RESULTS

Among AF patients, the ischaemic stroke IR was 0.51%/py in OAC users and 1.05%/py in non-users (aHR 0.47 [0.37-0.59]). Intracranial haemorrhage IR was 0.28%/py in OAC users and 0.19%/py in non-users (aHR 1.23 [0.88-1.72]). Oral anticoagulant use was associated with an increased risk of major bleeding (aHR 1.37 [1.16-1.63]) but lower risk of the combined outcome of ischaemic stroke, major bleeding, and mortality (aHR 0.57 [0.51-0.63]). Non-anticoagulated individuals with AF had higher risk of ischaemic stroke compared to non-AF individuals with the same risk profile (aHR 2.47 [2.17-2.81]).

CONCLUSIONS

In AF patients at intermediate risk of stroke, OAC use was associated with overall favourable clinical outcomes. Non-anticoagulated AF patients had higher risk of ischaemic stroke compared to the general population without AF with the same risk profile.

Validity of Simple Algorithms to Identify Recurrence of Intracerebral Hemorrhage in Two Danish Nationwide Registries

Purpose

Danish registries could be an attractive resource for studies of recurrent intracerebral hemorrhage (re-ICH). We developed and validated algorithms to identify re-ICH in the Danish Stroke Registry (DSR) and the Danish National Patient Registry (DNPR).

Patients and Methods

Using multiple sources, we followed-up an inception cohort with verified first-ever spontaneous ICH (n = 2528) for their first re-ICH in 2009-2018 (study period). We used verified cases of re-ICH (n = 124) as the gold standard to assess the performance of register-based algorithms for identifying re-ICH. For each cohort member, we traced events of re-ICH (ICD-10-code I61) in the study period according to DSR and DNPR, respectively. For each registry, we tested algorithms with a blanking period (BP) - ie, a period immediately following the index ICH during which outcome events were ignored - of varying length (7 days-360 days). The algorithm with the shortest BP that returned a positive predictive value (PPV) of ≥80% was considered optimal. We also calculated negative predictive value (NPV), sensitivity, and specificity of each algorithm and [95% confidence intervals] for all proportions.

Results

The optimal algorithm for DSR (BP 30 days) had a PPV of 89.5% [82.2-94.0], NPV 98.8% [98.2-99.1], sensitivity 75.8% [67.6-82.5], and specificity 99.5% [99.2-99.7]. The optimal algorithm for DNPR (BP 120 days) had a PPV of 80.6% [71.7-87.2], NPV 98.1% [97.5-98.6], sensitivity 63.7% [55.0-71.6], and specificity 99.2% [98.8-99.5].

Conclusion

Simple algorithms accurately identified re-ICH in DSR and DNPR. Compared with DNPR, DSR achieved higher PPV and sensitivity with a shorter BP. The proposed algorithms could facilitate valid use of DSR and DNPR for studies of re-ICH.

Association of Race/Ethnicity With Oral Anticoagulant Use in Patients With Atrial Fibrillation: Findings From the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II

Importance

Black and Hispanic patients are less likely than white patients to use oral anticoagulants for atrial fibrillation. Little is known about racial/ethnic differences in use of direct-acting oral anticoagulants (DOACs) for atrial fibrillation.

Objective

To assess racial/ethnic differences in the use of oral anticoagulants, particularly DOACs, in patients with atrial fibrillation.

Design, Setting, and Participants

This cohort study used data from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II, a prospective, US-based registry of outpatients with nontransient atrial fibrillation 21 years and older who were followed up from February 2013 to July 2016. Data were analyzed from February 2017 to February 2018.

Exposures

Self-reported race/ethnicity as white, black, or Hispanic.

Main Outcomes and Measures

The primary outcome was use of any oral anticoagulant, particularly DOACs. Secondary outcomes included the quality of anticoagulation received and oral anticoagulant discontinuation at 1 year.

Results

Of 12 417 patients, 11 100 were white individuals (88.6%), 646 were black individuals (5.2%), and 671 were Hispanic individuals (5.4%) with atrial fibrillation. After adjusting for clinical features, black individuals were less likely to receive any oral anticoagulant than white individuals (adjusted odds ratio [aOR], 0.75 [95% CI, 0.56, 0.99]) and less likely to receive DOACs if an anticoagulant was prescribed (aOR, 0.63 [95% CI, 0.49-0.83]). After further controlling for socioeconomic factors, oral anticoagulant use was no longer significantly different in black individuals (aOR, 0.78 [95% CI, 0.59-1.04]); among patients using oral anticoagulants, DOAC use remained significantly lower in black individuals (aOR, 0.73 [95% CI, 0.55-0.95]). There was no significant difference between white and Hispanic groups in use of oral anticoagulants. Among patients receiving warfarin, the median time in therapeutic range was lower in black individuals (57.1% [IQR, 39.9%-72.5%]) and Hispanic individuals (51.7% [interquartile range {IQR}, 39.1%-66.7%]) than white individuals (67.1% [IQR, 51.8%-80.6%]; P < .001). Black and Hispanic individuals treated with DOACs were more likely to receive inappropriate dosing than white individuals (black patients, 61 of 394 [15.5%]; Hispanic patients, 74 of 409 [18.1%]; white patients, 1003 of 7988 [12.6%]; P = .01). One-year persistence on oral anticoagulants was the same across groups.

Conclusions and Relevance

After controlling for clinical and socioeconomic factors, black individuals were less likely than white individuals to receive DOACs for atrial fibrillation, with no difference between white and Hispanic groups. When atrial fibrillation was treated, the quality of anticoagulant use was lower in black and Hispanic individuals. Identifying modifiable causes of these disparities could improve the quality of care in atrial fibrillation.